1. Field of the Invention
The present invention relates to a method and a device for winding a magnetic tape, such as winding a magnetic tape of prescribed length from a source roll of a magnetic tape to a small tape winding body, rewinding a magnetic tape from a tape winding body to another tape winding body, winding a magnetic tape of large width for a source "roll", and winding a magnetic tape of large width to a plurality of tape winding bodies while slitting the tape.
2. Background of the Invention
A process of manufacturing a magnetic tape such as an audio cassette tape, a video cassette tape, a memory tape or a broadcasting video tape includes a step of winding a magnetic tape of prescribed length from a source roll of a large-length tape to a small tape winding body such as a reel and a hub, a step of rewinding a magnetic tape from a tape winding body to another tape winding body, a step of winding a magnetic tape of large width as a source tape, a step of winding a magnetic tape slit from another magnetic tape, and so forth. When the magnetic tape is wound on the tape winding body in the process of the winding or the rewinding, the tape may vibrate in the direction of the thickness of the tape and this vibration can fluctuate due to the physical properties of the magnetic tape and those of the tape winding body so that each side edge of the tape wound on the winding body is unneatly overlaid on itself. The higher that the speed of the winding is, the more unneatly the side edge is overlaid on itself.
A magnetic tape whose side edge is unneatly overlaid on itself as described above has problems that the external appearance of the wound tape housed as a commercial product in a magnetic tape cassette is bad. Furthermore, the side edge is likely to be damaged resulting in various troubles such as the deterioration of the electromagnetic converting properties of the tape. The unneat overlaying is a serious drawback, particularly for a magnetic video tape for high-density recording, because an audio signal or a tuning signal is recorded near the side edge of the tape. For these reasons, in a conventional process of manufacturing a magnetic tape, the wound states of all magnetic tapes are visually inspected or the like after a winding process or a rewinding process. Since the inspection takes much time and money, the inspection is a major disadvantage in the magnetic tape manufacturing process.
In the conventional system shown in FIG. 1, a belt 15 made of a relatively soft nonwoven fabric or the like is provided between one flange of the tape winding body 2 and one side edge of the magnetic tape T to push the side edge of the tape T under relatively high pressure while the belt is supported by a roller 17 or the like and wound at a low constant speed from a belt send-out member 16 to a belt winding member 18 so as to neatly wind the tape.
In the neat winding system, described above, it is desirable to increase the pressure to the belt 15 in order to obtain high efficiency. However, since the belts 15 are placed in direct contact with the magnetic tape T in the above-mentioned system, there are various problems that the magnetic layer of the tape T is worn or the fibers of the nonwoven fabric come off to locally hinder recording on the tape T, inappropriate pressure acts to deform the tape T or damage its side edge, and so forth. For that reason, the system does not function properly. In addition, since the wear and tear of the neat winding system is large, it has disadvantages with regard to its cost and maintenance as well.
In addition to the neat winding method using the belt 15 or the like as described above, there has been proposed another neat winding method using a pressure disk 30 as shown in FIG. 2.
In this case, a tape reel 2 having a single flange 2a at one side is mounted on a rotary shaft 34. The pressure disk 30 formed of synthetic resin is mounted on the rotary shaft 34 so as to be slidable axially and rotatable in synchronism with the tape reel 2. In other words, when a magnetic tape T is taken up by the tape reel 2, the tape edge of the magnetic tape T is pressed toward the flange 2a by the pressure disk 30 (by the force according to its own weight or the like). However, the increase in pressure of the pressure disk 30 required for performing neat winding has induced various disadvantages, such as injury of the tape edge, transformation of the tape, unfitness for high-speed winding and the like, similarly to the case of the system of FIG. 1.